Hey guys,

I'm thinking of doing the front coil-over conversion offered for GM cars by QA-1.

It seems to me, that when the suspension is under compression the only thing holding the spring in would be the lower shock bolts, and when uncompressed only the top shock mount.
Both of these areas incorporating relatively small fasteners seem to me to be questionable in pull-thru and push-thru strength for a heavy highway-driven vehicle.

I like the idea of the stock coil spring being contained bewtween frame and a-arm in substantial and shaped pockets. The QA-1 uses the frame pocket only. Those tiny little shock bolts on the bottom shock mount and the stud with nuts on the top just don't give me a feeling of confidence in a big block car driven enthusiastically, that must for reasons remain absolutely reliable at all times, not to mention of course general highway safety.

I drive my car on real-world roads, with sudden surprise crummy street repairs, drainage, RR tracks, etc. All the things that make us hate rattles.
1966 El Camino, ZZ454, 4-speed.

Any comments?


Part II:

Any comments on the lower A-arms offered by Global West? The pivoting lower coil spring mount gives me pause for thought in strength issues as well.
In my experience, real road cars need to be kept fairly simple and very stout.


Thanks !

Eric

I have wondered the same thing myself. I would seem to need more beef to handle the 4000 lb. and up loading. You would think the bottom mounting would need to be strengthened beyond the original design. The OEM setup only needed to handle shock absorber loads, very little in compression.

I would worry less about the extension limit since the impact loads will be reduced by normal/typical shock dampening. Unless you run drag race dampening...

I actually see very little benefit of running these coil overs on a Chevelle front end. All they really bring to the part is bling.

Now on a strut type front end like recent Mustangs the coil over allows for a much lighter spring because it radically changes the motion ratio. That can be a good thing.

Steve

I actually see very little benefit of running these coil overs on a Chevelle front end. All they really bring to the part is bling.

Now on a strut type front end like recent Mustangs the coil over allows for a much lighter spring because it radically changes the motion ratio. That can be a good thing.

Steve

Bingo! As Steve states, coil overs on modified McPherson strut cars changes the motion ratio thus enabling the selection of lighter springs. Adjustability is an added bonus, but there are other ways of doing it on our rides. Some members on here have proved that.

You also have the arguement of easily changing corner weights and adding wedge into the suspension, but in reality and in my opinion the vast majority of folks running these coil overs on our A-bodies do it for bling. Not that I blame them...they're kind of :cool:

Joe

I run the QA-1 R series coilovers, Global West upper/lower tubular arms along with 2nd gen Camaro spindles on my '70.
Works for me...track tested at 134 mph numerous times. ;)
Handles just fine on the street, too. I like the shock adjustability function.

Adjustability is great, but I have a set home to install also. I took a good look at this and wondered the same thing regarding the lower bolts as well as a reinforcement for the top. I don't think the top is an issue. Struts have one stud at the top. A reinforcing plate can very easily be installed to beef this are a up is desired. At the bottom, I had considered beefng the attachment point via a couple of methods. A reinforcing plate can be fabbed to distribute the load out to the spring pocket. Another way may be to get a set of old lowers, cut the spring pocket out and use this section to double up the sping pocket of your existing lower. In reality, QA1 has been building these for some time, and doesn't recommend any mods, although the tubular lowers would be nice.

I installed the front QA1 coil overs on my 69 Chevelle this spring. And I have to say I questioned the lower shock mounting strength. Trust me when I say it will be fine. There is a video of it at yellowbullet.com under milan heads up shootout, last event video's and then wheelie contest. My car is the Lemans blue 69 chevelle racing the Regal. 1.38 60' on the rear wheels. Tom

I should have mentioned that this kit was installed with stock A-arms and no reinforcements.

When I was considering QA1 coilovers for the front I talked to a QA1 engineer (not a sales rep or a tech rep, an engineer who helped design them) and voiced my concerns about the lower mounting integrity. He said the issue was very well researched and the stock lower arms were found to be more than sturdy enough to accept this mounting method and in thousands of their own test miles and those of people who are running them now they have absolutely no reports of the lower mounting failing. I also spoke with other local suspension experts not affiliated with QA1 and got similar reports.

He did add that if you wish to use your stock lower control arms, do have them cleaned up and inspected for rust or road damage in the spring pocket, bushing mounts and ball joint mount areas and to replace or repair the control arm if any damage is found. Of course such inspections are a good idea whether you are switching to coil overs or running a stock style spring mounting. He did stress that it is necessary, as prominently mentioned in the instructions, to fully grind off the lower shock mounting nuts so the coilover mount can bolt flush to the lower control arm metal.

I took another look at the QA1's. I had completely forgotten that the top of the spring sits in the stock frame pocket. The bottum mount is about 1/2" thick. The unit is bolted in with Grade 8 bolts at the bottum. Also, if you ever really took notice, probably only about 3" of coil spring ever makes contact with the seat of the lower control arm.

Another thing that occurs to me upon rereading the original post is that it needs to be mentioned that the QA1 coilovers' lower mount bolts to the TOP side of the lower control arm, not the bottom side like the stock style shocks. In essence, the coilovers do NOT present a bolt pull- or push-through situation. The weight of the car rests on the lower mount of the coilover which is 1/2 inch billet aluminum. It is more than up to the task. The heavy steel of the control arm is also up to the task or they wouldn't have held the car up for all these years. The only pressure the lower mount bolts encounter are some moderate shearing force. The only longitudinal forces on the bolts are also at an extreme minimum since when the control arm is rising it is pressing up against the coilover lower mount and when it is going down the force of the spring is pressing the mount against the control arm thus reducing the force placed on the bolt itself.

If the bolts were to fail, the lower end of coilover would remain in the spring pocket though it may rattle around like crazy. If the lower mount were to entirely fail the bottom the coilover would drop about 2-3 inches (depends on where you have the springs set) until the lower spring mount contacts the spring pocket on the coil over. Even in this extremely unlikely situation no complete loss of suspension would occur.

And as mentioned above, at the upper end the spring rests against the frame as in a stock style spring. These are NOT a "fully captured spring" coilover in which the spring is entirely contained on the shock body/coilover itself.